3(2h)-isoquinolones

ABSTRACT

NEW 2-SUBSTITUTED-3(2H)-ISOQUINOLONES AND 2-SUBSTITUTED-3-ALKOXYISOQUINOLINES ARE DISCLOSED. THEY ARE ORALLY ACTIVE HYPOTENSIVES AND PERIPHERAL VASODILATORS WITH AN EXTENDED DURATION OF ACTION; REPRESENTATIVE EMBODIMENTS OF THIS INVENTION ARE 6,7-DIMETHOXY-2-METHYL-1: VERATRYL-3(2H)-ISOQUINOLONE HYDROCHLORIDE, 2-ALLYL-6,7DIMETHOXY-1-VERATRYL-3(2H)ISOQUINOLONE HYDROCHLORIDE, 2- CYCLOPROPYL- 6,7-DIMETHOXY -1-VERTRYL3(2H)-ISOQUINILONE HYDROCHLORIDE, 2-AMINO-6,7-DIMETHOXY-1-VERTRYL-3(2H)-ISOQUINOLONE HYDROCHLORIDE, AND 3-ETHOXY-6,7-DIMETHOXY-1-VERTRYLISOQUINOLINE.

United States Patent 3,798,225 3(2H)-ISOQUINOLONES William Eugene Kreighbaum and William 'Iimmey Comer,

Evansville, Ind., assignors to Mead Johnson 8: Company, Evansville, Ind. No Drawing. Filed Sept. 27, 1971, Ser. No. 184,197 Int. Cl. (107d 35/28 US. Cl. 260-286 R 19 Claims ABSTRACT OF THE DISCLOSURE New 2-substituted-3 (2H)-isoquinolones and 2-substituted-3-alkoxyisoquinolines are disclosed. They are orally active hypotensives and peripheral vasodilators with an extended duration of action. Representative embodiments of this invention are 6,7-dimethoxy-2-methyl-lveratryl 3(2H) isoquinolone hydrochloride, 2-allyl-6,7- dirnethoxy 1 veratryl 3(2H) isoquinolone hydrochloride, 2 cyclopropyl 6,7 dimethoxy l-veratryl- 3(2H) isoquinolone hydrochloride, 2-amino-6,7-dimethoxy 1-veratryl-3 (2H)-isoquinolone hydrochloride, and 3-ethoxy-6,7-dime.thoxy-l-veratrylisoquinoline.

BACKGROUND OF THE INVENTION This invention is concerned with certain heterocyclic carbon compounds having one hetero-N-atom. More particularly, it relates to 3(2H)isoquinolones and 3-alkoxyisoquinolines which have hypotensive and peripheral vasodilating properties. Although the compounds of the present invention are of the same basic ring system as the isoquinoline, 6,7-dimethoxy-l-veratryl-3-isoquinolinol described by G. N. Dorofeenko and V. G. Korobkova, J. Gen. Chem, U.S.S.R., 40, 230 (1970), they differ substantially in biological activity. Thus, for example, the compounds of the present invention are active orally as hypotensive and peripheral vasodilating agents whereas the prior art isoquinolinol is essentially inactive.

SUMMARY OF THE INVENTION The present invention is concerned with novel 2-substituted-3 (2H)-isoquino1ones of Formula I and 3-alkoxyisoquinolines of Formula II and with non-toxic pharmaceutically acceptable acid addition salts thereof. These substances have utility as peripheral vasodilators and hypotensive agents.

BJO=O R Ioro l OH; OK. (i111: 0R

0R -OR Formula I Formula II In Formulas I and II above, R represents lower alkyl. The R N-substituent identifies a member of the group consisting of hydroxy, amino, lower alkylamino, lowe'r dialkylamino, lower alkyl, alkenyl, cycloalkyl of from 3 to 5 carbon atoms inclusive, and phenylalkyl having up to carbon atoms. Said phenylalkyl may have substituents attached to the phenyl ring which are selected from halogen, lower alkyl, methylenedioxy, and up to 3 lower alkoxy groups. R in Formula H, represents lower alkyl, alkenyl, cycloalkyl of from 3 to 5 carbon atoms inclusive, and benzyl.

It is to be understood that the terms lower alkyl and lower alkoxy when used herein contemplates both straight and branched chain groups, containing from 1 to about 4 carbon atoms. Illustrative of such groups are methyl, ethyl, propyl, isopropyl, l-butyl, l-methylpropyl,

3,798,225 Patented Mar. 19, 1974 ice It is to be understood that the term non-toxic pharmaceutically acceptable acid addition salts used herein and in the appended claims denotes a combination of the 3(2H)-isoquinolones and isoquinolines of Formulas I and II with suitable non-toxic inorganic or organic acids to provide salts having physical properties including re quisite stability adaptable for pharmaceutical formulations. Examples of non-toxic pharmaceutically acceptable acid addition salts of the compounds of Formulas I and II are those formed with sulfuric, hydrochloric, phosphoric, hydrobromic, hydroiodic, sulfamic, methanesulfonic, benzenesulfonic, para-toluenesulfonic, acetic, lactic, succinic, malic, maleic, mucic, tartaric, citric, gluconic, benzoic, cinnamic, isethionic, fumaric, and related acids.

The 3(2H)-isoquinolones of Formula I and acid addition salts thereof have a distinctive light to deep yellow color in the solid state. This color is attributed to the ortho-quinoid structure as represented by Formula I. The ortho-quinoid structure is consistent with ultraviolet, nuclear magnetic reasonance, and infrared spectra for the 3(2H)-isoquinolones of Formula I rather than other tautomeric forms such as those represented by Formula Ia and Formula Ib. Formula la in which R and R are methyl groups has been reported by I. W. Elliott, J. Heterocycl. Chem., 7, 1229-1230 (1970).

1 =0 R O 0H 91H O R (3H 0 R Formula Ia Formula Ib A variety of methods may be employed to produce the novel isoquinolones of this invention. One particularly preferred method is the condensation of an R -NH intermediate with a lactone corresponding to Formula III wherein R and R have the meaning given above.

Formula III The condensation is carried out in an inert organic solvent as a reaction medium. Tetrahydrofuran is a preferred sol-vent but other solvents such as benzene, toluene, dioxane, acetonitrile, chloroform and the like are also useful. Preferably, the reaction is conducted at about 25 C., although this temperature is not critical and reaction temperatures appreciably above and below are also operable.

After the condensation is complete, the solvent is evaporated and the residue treated with hydrochloric acid to provide a hydrochloride salt of the isoquinolones of Formula I. Other non-toxic pharmaceutically acceptable acid addition salts may be prepared by treating the residue with other suitable organic or inorganic acids. 7

Acid addition salts of the present invention can be converted to the corresponding free bases by reaction with a basic reagent such as aqueous ammonia. Although both the free base and salt forms of the compounds of the present invention are useful for the purposes of the invention, salts are generally preferred as they are relatively more stable than free base forms.

The lactone condensation probably involves formation of 1-hydroXy-3(2H)-isoquinolone intermediates which in presence of acid undergo dehydration to form 3-(2H)- isoquinolones of [Formula I. Illustrative of such an intermediate is 1,4-dihydro-l-hydroxy 6,7 dimethoxy 2- methyl-lveratry1-3(2H)-isoquinolone which is obtained by the condensation of methylamine with the lactone, 1-(3,4 dimethoxybenzylidene) 6,7 dimethoxy-3-isochromanone. In the presence of hydrochloric acid, this intermediate converts rapidly to 6,7-dimethoxy-2-methyl- 1-veratryl-3(2H)-isoquinolone hydrochloride.

Lactones identified by general Formula lII above are obtained by dehydrating keto acids of Formula IV wherein R has the above meaning in a mixture of acetic anhydride, glacial acetic acid and concentrated sulfuric acid. This method is essentially that described by I. W. Elliott, supra, for the preparation of 1-(3,4-dimethoxybenzylidene)-6,7-dimethoxy-3-isochromanone from the keto acid 2-(3,4-dimethoxyphenylacetyl) 4,5 dirnethoxyphenylacetic acid.

H OR

Formula IV.

'2- (3,4-dimethoxyphenylacetyl) -4,5-dimethoxyphenylacetic acid,

2-(3,4-diethoxyphenylacetyl)-4,5-diethoxyphenylacetic acid,

2-(3,4-diisopropoxyphenylacetyl)-4,5-diisopropoxyphenylacetic acid,

2-(3,4-di-n-butoxyphenylacetyl)-4,5-di-n butoxyphenylacetic acid,

which are obtained from intermolecular acylation of the 3,4-dial koxyphenylacetic acids:

3,4rdimethoxyphenylacetic acid, 3,4-diethoxyphenylacetic acid,

Some of the isoquinolones of Formula I may also be produced by cyclization of keto acids of Formula IV with R NH intermediates in acetic acid.

An alternate method of preparing isoquinolones of general Formula I wherein R is methyl is by alkylation of a 6,7-dialkoxy-l (3,4 dialkoxybenzyl)-3-isoquinolinol with methyl iodide in the presence of a base such as sodium methoxide. The predominate product is the N- alkylated isoquinolone with a minor amount of a 3- methoxyisoquinoline of Formula H.

Another method of preparing 3-methoxyisoquinolines of Formula II is by alkylation of the silver salt of 6,7- dialkoxy-l-(3,4-dialkoxybenzyl) 3 isoquinolinols with methyl iodide.

isoquinolines of Formula II are preferably obtained from corresponding 6,7-dialkoXy-l-(3,4-dialkoxy benzyl)- 3-isoquinolinols by reaction with a R X-alkylating agent in a reaction inert organic solvent such as, e.g., benzene, toluene, dioxane and preferably acetone, at moderately high temperatures, e.g., between about 60 and C. in the presence of bases, e.g., alkali metal carbonates such as potassium carbonate. R is as defined above and the symbol X refers to the acid residue of a reactive ester grouping such as e.g., a bromide, iodide, chloride, sulfate, tosylate or mesylate.

An alternate method of preparing isoquinolines of Formula II is by alkylation of corresponding 6,7-dialkoxyl-(3,4 dialkoxybenzyl) 3 isoquinolinols with a trialkyloxonium fluoroborate as described in L. F. 'Fieser and M. Fieser, Reagents for Organic Synthesis, page 1210 (Wiley, 1967).

The compounds of the present invention identified by Formulas I and II have hypotensive and peripheral vasodilating properties and are, therefore, useful in treating conditions in mammals responsive to administration of such agents. They are orally active and when compared to papaverine in the dog have a consideraby longer duration of action.

These valuable pharmacological properties can be demonstrated by standard pharmacological methods. For example, hypotensive and peripheral vasodilating activity are measured in anesthetized dogs according to the following procedure. A tracheotomy is performed and the animal is ventilated mechanically and arranged for recording arterial blood pressure, aortic blood llow, right ventricular contractile force and heart rate. The test agent is administered by a rubber catheter inserted into the duodenum through the pyloric sphincter via a small incision in the stomach wall (duodenal administration is considered to be equivalent to oral administration by mouth or by stomach tube).

Illustrative of the cardiovascular activity exhibited by the compounds of the present invention in this test is that obtained with a preferred compound, 6,7-dimethoxy- Z-methyl 1 veratryl-3 (2H)-isoquinolone hydrochloride, which at a dose of 5 mg./kg. body weight produced a 30% decrease in diastolic blood pressure and a 19% decrease in total peripheral resistance. Mean systemic blood pressure divided by mean aortic blood flow is taken as a measure of total peripheral resistance. At a similar dose, both papaverine, which is a welbknown peripheral vasodilator and 6,7-dimethoxy-1-veratryl-3-isoquinolinol, a prior art isoquinoline, are devoid of significant cardiovascular activity.

'Selective hypotensive and peripheral vasodilating effects relative to the ventricular contractile force and heart rate are produced by the instant compounds when compared to papaverine. That is to say, desirable hypotensive and peripheral vasodilating responses are obtained with substantially less adverse cardiac effects, e.g., increased ventricular contractile force and heart rate, than is produced by an effective dose of papaverine.

There can be mentioned by way of Example the following compounds as those particularly preferred for oral hypotensive and peripheral vasodilating activity:

6,7 -dimethoxy-2-methyl- 1-veratryl-3 (2H) isoquinolone hydrochloride,

2-allyl-6,7-dimethoxy-l-veratryl-3 2H) isoquinolone hydrochloride,

2-cyclopropyl-6,7-dimethoxy-1-veratryl-3 (2H) isoquinolone hydrochloride,

2-amino-6,7-dimethoxy-1-veratryl-3 (2H) isoquinolone hydrochloride.

The process of the present invention for producing a hypotensive and peripheral vasodilating effect in a mammal is carried out by systemic administration of an effective non-toxic dose of the 3(2H)-isoquinolones of Formula I and 3-alkoxyisoquinolines of Formula II ranging from about 0.05 to 20 mg./kg. body weight of the mammal. It is intended by systemic administration to include both oral and parenteral routes. Oral administration is preferred, although parenteral routes, e.g., intramuscular, intravenous, intraperitoneal and subcutaneous administration may also be employed. The dosage will vary with the form of administration and the particular compound chosen. Generally, the compound is administered at a dosage substantially less than the dose of the compound which is thought to be effective. Thereafter, in conformity with accepted therapeutic methods, the dosage is increased by small increments until the desired hypotensive or vasodilating effect is reached.

The compounds which constitute this invention and their methods for preparation will appear more fully from the consideration of the following examples which are given for the purpose of illustration only and are not to be construed as limiting the invention in spirit or scope.

EXAMPLE 1 6,7-dimethoxy-2-methyl-l-veratryl-3 (2H) isoquinolone hydrochloride (A) Alkylation of 6,7-dimethoxy-1-veratryl-3-isoquinolinol.Sodium methoxide (2-6.0 g., 0.48 mole) is added portion-wise to a refluxing suspension of 6,7-dimethoxyl-veratryl-3-isoquinolinol (28.4 g., 0.08 mole), methyl iodide (224 g., 1.60 mole) and 400 ml. of methanol over a 24 hr. period. The consumption of the isoquinolinol is monitored by thin layer chromatography (silica gel developed in 9:1 chloroform methanol) and when complete the reaction is filtered and the filtrate concentrated. Residual oil which remains is taken up in ethyl acetate and washed with three 300 ml. portions of water. After drying over potassium carbonate, the ethyl acetate solution is filtered through decolorizing charcoal and acidified with 5 N ethanolic hydrogen chloride to provide a yellow solid. Crystallization of this material from methanol-ethyl acetate alfords analytically pure 6,7-dimethoxy- 2-methyl 1 veratryl-3(2H)-isoquinolone hydrochloride, 13.8 g. (43%), M.P. 223.0-225.0 C. (dec.) (corn).

Analysis.Calcd. for C H NO -HCl (percent): C, 62.14; H, 5.96; N, 3.45. Found (percent): C, 62.16; H, 5.96; N, 3.45.

Absorption Spectra given below are consistent for the hydrochloride salt of the structure depicted by the formula Ultraviolet: A ethanol), 400 (e, 6300); 318 (e, 4500); 305 (e, 4500); 258 (6, 63,500); 229 (e, 23,000) millimicrons.

NMR: 6 (DMSO-d tetramethylsilane reference), 3.7-4.2 (5s, 15, N-CHg, OCH 4.9 (s, 2, CH 6.3- 7.2 (3ArH), 7.3-7.6 (3ArH).

(B) Cyclization of ketoacid with methylamine acetate.-3,4 dimethoxyphenylacetic acid g., 0.637 mole) is added in one portion to 500 ml. of polyphosphoric acid at 75 C. The reaction mixture is then stirred for 15 minutes and quenched in 4 liters of water. After the mixture stands overnight, the tacky yellow brown solid which forms is collected, washed with water and dried to provide 114 g. of product having a melting point of -145 C. Crystallization of this material from ethyl acetate with decolorizing charcoal yields 69.3 g. (58%) of the ketoacid 4,5-dimethoxy-2-[(3,4-dimethoxyphenyl)acetyl]phenylacetic acid, M.P. ISO-153 C.

A mixture of the ketoacid (7.5 g., 0.02 mole), methylamine acetate (9.1 g., 0.1 mole) in 25 ml. of glacial acetic acid is refluxed for 2 hrs. and then quenched in 500 ml. of water. This mixture is extracted with chloroform, the chloroform extract dried over magnesium sulfate, stirred with decolorizing charcoal and filtered. Concentration of the filtrate in vacuo provides an oil which is taken up in ethyl acetate and acidified to a pH of 2 with 5 N ethanolic hydrogen chloride. The resulting solid is collected and crystallized from methanol-ethyl acetate to provide analytically pure 6,7-dimethoxy 2 methyl 1 veratryl- 3(2H) isoquinolone hydrochloride, M.P. 234-236 C. (dec.) (uncorr.). v

Analysis.Calcd. for C H NO HCl (percent): C, 62.14; H, 5.96; N, 3.45; Cl, 8.74. Found (percent): C, 62.00; H, 6.21; N, 3.61; Cl, 8.57.

(C) Condensation of lactone with methylamine-A mixture of the ketoacid 4,5-dimethoxy-2-[(3,4-dimethoxyphenyl)acetyl]phenylacetic acid (10.0 g., 0.0267 mole), 17 ml. of acetic anhydride, 17 ml. of glacial acetic acid and 2 drops of concentrated sulfuric acid is heated at steam bath temperature for 4 hrs. After standing at room temperature overnight the mixture is filtered and the filter cake washed with ether and air dried to provide 7.0 g. (74%) of the lactone 1-(3,4-dimethoxybenzylidene)- 6,7-dimethoxy-3-isochromanone as a white solid, M.P. 162-165 C.

The lactone (3.6 g., 0.01 mole) is suspended in 100 ml. of dry tetrahydrofuran and gaseous methylamine is passed therein until complete solution is obtained. The mixture is left standing overnight at room temperature and concentrated under reduced pressure to provide a residual oil which is taken up in methanol and acidified with 5 N ethanolic hydrogen chloride. The acidified solution is cooled and the precipitated solid is collected and crystallized from methanol-ethyl acetate to provide 3.1 g. (76.5%) of 6,7-dimethoxy-2-methyl-1-veratryl-3(2H)-isoquincslone hydrochloride, M.P. 233-236 C. (dec.) (uncorr.

EXAMPLE 2 6,7-diethoxy-2-methyl- 1- 3,4- diethoxy) benzyl-3 (2H) isoquinolone hydrochloride Following the procedure of Example 1B but substituting 3,4 diethoxyphenylacetic acid in lieu of 3,4-dimethoxyphenylacetic acid there is obtained 6,7-diethoxy-1-(3,4- diethoxy)benzyl-3 (2H)-isoquinolone hydrochloride, M.P. 182.5-187.5 C. (dec.) (corn) from ethyl acetate.

Analysis.Calcd. for C H NO -HCl (percent): C, 64.99; H, 6.98; N, 3.03. Found (percent): 64.71; H, 6.82; N, 3.19.

Ultraviolet: k (95% EtOH), 400 (e, 6200); 320 (e, 5500); 307 (e, 5400); 258 (e, 67,000) millimicrons.

NMR: 6 (deuterochloroform, tetramethylsilane reference), 1.4 (t, 12, CH 3.8 (s, 3, NCH 3.9 (q, 8, CH O); 4.6 (s, 2, CH 6.2-7.2 (6, ArH).

A 7 EXAMPLE 3 2-ethyl-6,7-dimethoxy-1-veratry1-3(2H)-isoquino1one hydrochloride Following the procedure of Example 1B, but substituting ethylamine acetate (M.P. 85-90 C.) for methylamine acetate there is obtained 2-ethyl-6,7-dimethoxy-l-veratryl- 3 (2H)-isoquinolone hydrochloride, as a yellow solid, M.P. 219.5-221.5 C. (dec.) (corr.).

Analysis.Calcd. for C H NO -HCl (percent): C, 62.94; H, 6.24; N, 3.34. Found (percent): C, 63.06; H, 6.28; N, 3.29.

Ultraviolet: A (95% EtOH), 402 (e, 5400); 319 (e, 4300); 306 (s, 4600); 258 (6, 60,500) millimicrons.

NMR: 6 (DMSO-d tetramethylsilane reference), 1.3 (t, 3, CH 3.8-4.0 (12, OCH 4.6 (q, 2, NCH 5.0 .(s, 2, CH 6.6-7.8 (6, ArH); 10.5 (1, H

EXAMPLE 4 2-allyl-6,7-dimethoxy-1-veratry13 (2H) -isoquinolone hydrochloride Following the procedure of Example 1C while employing a 1:3 molar ratio of the lactone to allylamine there is obtained 2 allyl-6,7-dimethoxy-1-veratryl-3 (2H)-isoquinolone hydrochloride as a yellow solid, M.P. 182.5-184.5 C. (dec.) (corr.).

Analysis.-Calcd. for C H NO -HCl (percent): C, 63.96; H, 6.08; N, 3.24. Found (percent): C, 64.16; H, 5.91; N, 3.33.

Ultraviolet: A (95% EtOH), 403 (e, 4900); 319 (e, 3900); 308 (E, 3600); 259 (6, 57,000) millimicrons.

NMR: 6 (DMSO-d tetramethylsilane reference), 3.7-4.0 (12, OCH 4.9-5.2 (4, (CH 5.4-6.3 (3, --CH=CH 6.5-7.6 (6 ArH).

EXAMPLE 5 2-cyclopropyl-6,7-dirnethoxy-1-veratry1-3 2H) isoquinolone hydrochloride Following the procedure of Example 1C while employing 0.03 mole of the lactone and 0.088 mole of cyclopropylamine there is obtained 10.7 g. (82.5%) of 2-cyclopropyl-'6,7-dimethoxy-l-veratryl 3 (2H) isoquinolone hydrochloride as 'a yellow solid, M.P. 214.0-215.0 C.

(dec.) (corr.).

Analysis.Calcd. for C H NO -HCI (percent): C, 63.96; H, 6.07; N, 3.24. Found (percent): C, 63.73; H, 6.12; N, 3.07.

Ultra violet: A (95% EtOH), 400 (e, 5400); 320 (e, 5200); 308 (e, 4800); 258 (e 64,400); 229 (6, 23,300) millimicrons.

NMR: 6 (DMSOd tetramethylsilane reference), 1.3 (m, 4, (CH 3.3-4.0 (13, OCH;,, CH); 5.1 (s, 2, CH 6.4-7.6 (6, ArH); 8.3 (1, H+).

EXAMPLE 6 2-benzyl-6,7-dimethoxy-1-veratry1-3 (2H) -isoq uinolon hydrochloride Following the procedure of Example 1B but substituting benzylamine acetate for methylamine acetate there is obtained 2-benzyl-6,7-dimethoxy 1 veratryl-3(2H)-isoquinolone hydrochloride as 'a yellow solid, melting at 145.0 C., resolidifying and melting again at 208.5209.5 C. (dec.) (corr.)

Analysis.Calcd. for C H NO -I-ICI (percent): C, 67.28; H, 5.86; N, 2.91. Found (percent): C, 67.10; H, 5.96; N, 2.94.

Ultraviolet: A (95% EtOH), 400 (e, 5300); 320 (e, 5300); 308 (s, 4900); 260 (6, 61,700) millimicrons.

NMR: 6 (DMSO-d tetramethylsilane reference), 3.8-4.1 (12, OCH 4.7 (s, 2, CH 5.7 (s, 2, NCH 6.4- 8.0 (11, ArH); 8.5 (1, H+).

8 EXAMPLE 7 6,7 -dimethoxy-2- 3 ,4-dimethoxyphenethyl) -1-veratryl- 3 (2H) -isoquinolone hydrochloride A mixture of 4,5-dimethoxy-2-[(3,4-dimethoxyphenyl) acetyl]phenylacetic acid (10 g., 0.027 mole) and 3,4-dimethoxyphenethylamine carbonate (24 g., 0.106 mole) is refluxed for 4 hrs. and then quenched with 900 ml. of ice water. Adjustment of the pH of the solution to 6 with concentrated ammonium hydroxide and chilling affords 10 g. of white solid. The solid is taken up in 200 ml. of ethyl acetate, dried over magnesium sulfate and treated with decolorizing charcoal. Acidification of the solution with 5 N ethanolic hydrogen chloride and chilling for 3 hrs. in ice water provides 9 g. of white solid, M.P. 226- 229 C. This material is fractionally crystallized from methanol-ethanol-water (17:2:1) to give 6.1 g. of a white solid, M.P. 238-248 C. (dec.) and 1.9 g. of yellow solid, M.P. 218-220" C. (dec). Crystallization of the yellow solid from isoprop'anol yields 1.5 g. of 6,7-dimethoxy-2- (3,4 dimethoxyphenethyl) 1 veratryl-3(2H)-isoquinolone hydrochloride as a yellow powder melting at 215.5-219.0 C. (dec.) (corr.).

Analysis.Calcd. for C3UH33NO7HCI (percent): C, 64.80; H, 6.16; N, 2.52. Found (percent): C, 65.07; H, 6.12; N, 2.72.

Ultraviolet: A (95 EtOH), 400 (e, 6500); 320 (e, 6100); 308 (e, 5700); 259 (5, 72,300); 230 (a, 33,200) millimicrons.

NMR: 6 (deuterochloroform, tetramethylsilane reference), 3.1 (m, 2, CH 3.8-4.1 (4s, 18, OCH 4.5 (m, 2, CH 4.6 (s, 2, CH 6.4-7.2 (8, ArH); 8.3 (1, ArH).

EXAMPLE 8 2-amino-6,7- dimethoxy-1-veratryl-3 (2H) -isoquinolone hydrochloride Following the procedure of Example 1B but substituting hydrazine hydrate for methylamine acetate there is obtained 2-amino-6,7-dimethoxy-1-veratryl-3 (2H) -isoquinolone hydrochloride as a yellow solid, M.P. 206.0-207.0 C. (dec.) (corr.).

Analysis.-Calcd. for C H N O -HCl (percent): C, 59.04; H, 5.70; N, 6.89. Found (percent): C, 59.32; H, 5.84; N, 6.77.

- Ultraviolet: A (95% EtOH), 400 (e, 6400); 318 (e, 5100); 307 (e, 4900); 247 (6, 64,200) millimicrons.

NMR: 6 (DMSOd tetramethylsilane reference), 3.84.0 (12, OCH 5.0 (s, 2, CH 6.9-7.5 (6, ArH); 8.2 (s, 3, N-Hfi).

EXAMPLE 9 2-hydroxy-6,7-dimethoxy-1-veratryl-3 (2H -isoquinolone hydrochloride Aqueous sodium hydroxide (20 ml. of 5.15 N) added to a suspension of 4,5-dimethoxy-2-[(3,4-dimethoxyphen yl)acetyl]phenylacetic acid (10.0 g., 0.0267 mole) and hydroxylamine hydrochloride (4.9 g., 0.07 mole) in 50 m1. of water provides a clear solution which is heated for 1 hr. at C. The solution is stirred with decolorizing charcoal, filtered, acidified to a pH of 3 with concentrated hydrochloric acid, and then chilled to provide an amber gum which is separated by decanting the supernatant liquid. Triturating the gum with ethyl acetate aflords 2- (3,4 dimethoxyphenylacetyl) 4,5 dimethoxyphenylacetic acid oxime, M.P. 134138 C.

The oxime (2.6 g., 0.0066 mole) taken up in 10 ml. of acetic acid and 2 ml. of concentrated hydrochloric acid and stirred for 16 hrs. Concentration of the filtrate in vacuo affords a residue which is crystallized first from ethanolethyl acetate and then methanol to provide analytically pure 3.7 g. of 2-hydroxy-6,7-dimethoxy-1-veratryl-3(2H)- 210.0 C. (dec.) (corr.).

Analysis.-Calcd. for c,,H,,No,-Hc1 (percent): C, 58.89; H, 5.44; N, 3.43; CI, 8.69. Found (percent): C, 59.16; H, 5.31; N, 3.61; Cl, 8.67.

Ultraviolet: A (95% EtOH), 394 (e, 4400); 310 sh (e, 4400); 256 (6, 38,000) millimicrons.

NMR: 6 (DMSO-d tetramethylsilane reference), 3.8-4.0 (12, OCH 4.9 (s, 2, CH2); 6.9-7.6 (6, ArH); 10.5 (s, 2, OH, H+).

EXAMPLE 10 3,6,7-trimethoxy-l-veratrylisoquinoline hydrochloride A suspension of 6,7-dimethoxy-1-veratryl-3-isoquinolin- 01 3.6 g., 0.01 mile) in a mixture of 70 ml. of Water and 20 ml. of 1 N sodium hydroxide is stirred at 25 C. until the yellow isoquinolinol has turned white and the supernatant is colorless. The suspension is chilled, filtered, and the filter cake washed with 50 ml. of tetrahydrofuran. Air drying provides 4.0 g. (100%) of 6,7-dimethoxy-1-veratryl-3-isoquinolinol sodium salt as a white solid monohydrate, sintering at 250-260 C.

The sodium salt of 6,7-dimethoxy-1-veratryl-3-isoquinolinol (1.0 g., 0.0025 mole) is suspended in 20 ml. of absolute ethanol and 2% silver nitrate/ethanol is added dropwise thereto until further addition causes no more yellow-orange precipitate to form. The resulting suspension is stirred at 25 C. for 1 hr. in the dark and filtered. The yellow filter cake is washed first with 5 ml. of absolute ethanol then with 20 ml. of ether and air dried to provide 1 g. of 6,7-dimethoxy-1-veratryl-3-isoquinolinol silver salt.

Methyl iodide (34 g., 0.24 mole) is added to the silver salt in 15 ml. of ether and the mixture stirred for 16 hrs. in the dark. Dilution of the mixture with 125 ml. of tetrahydrofuran, filtering and concentrating the filtrate provides a solid residue. Crystallization of the residue from ether-methylene chloride aiIords 0.5 g. (49%) of 3,6,7- trimethoxy-l-veratrylisoquinoline free base as pale yellow crystals, M.P. 135l36 C.

The hydrochloride salt prepared by acidifying the free base with ethanolic hydrogen chloride is crystallized from methanol-isopropanol to analytically pure 3,6,7-trimethoxy-l-veratrylisoquinoline hydrodhloride las a pale yellow solid, melting at 1905-1940 C. (dec.) (crr.).

Analysis.Calcd. for C H NO -HCI (percent): C, 62.14; H, 5.96; N, 3.45. Found (percent): C, 62.37; H, 6.00; N, 3.36.

Ultraviolet: A (95 EtOH), 345 (e, 5700); 272 (e, 6900); 240 (e, 60,600) millimicrons.

NMR: 8 (DMSOd tetramethylsilane reference), s, 3.8-4.1 (5s, 15, OCH 4.5 (s, 2, CH 6.9-7.3 (6, ArH).

EXAMPLE 11 3-eth0xy-6,7-dimethoxy-l-veratrylisoquinoline Triethyloxonium fluoroborate prepared from boron fluoride etherate (6.81 g., 0.048 mole) and epichlorohydrin (3.33 g., 0.036 mole) according to the method of H. Meerwin, Org. Syn., 46, 113 1966) is taken -up in 100 ml. of dry methylene chloride and 6,7-dimeth0xy-1-veratryl- 3-isoquinolinol (10.8 g., 0.03 mole) in 20 ml. of methylene chloride added thereto. The mixture is stirred at 25 C. for 16 hrs., chilled and washed first with aqueous potassium carbonate and then with three 200 ml. portions of water. After drying the washed methylene chloride solution over magnesium sulfate and treating with decolorizing charcoal, the solvent is evaporated. Crystallization of the residue first from methanol-isopropyl alcohol and then firom acetonitrile and finally Iagain from methanol-isopropyl alcohol affords 4.1 g. (43%) of analytically pure 3-ethoxy-6,7-dimethoxy 1 veratrylisoquinoline as a White solid, M.P. 110.0-112.0 C. (corn).

-Analysis.-Calcd. for C H NO (percent): C, 68.92; H, 6.57; N, 3.65. Found (percent): C, 69.05; H, 6.53; N, 3.71.

Ultraviolet: x (CHCl 348 (e, 5500); 270 (e, 7300); 243 (5, 55,200) millimicrons.

NMR: 6 (deuterochloroform, tetramethylsilane reference), 1.3 (t, 3, CH 37-4.0 (4s, 12, OCHs); 4.4 (N, 2, OCH 4.5 (s, 2, CH Ar); 6.7-7.4 (6, ArH).

EXAMPLE l2 3-benzyloxy-6,7-dimetihoxy-1-veratrylisoquinoline A mixture of 6,7-dimethoxy-1-veratryl-3-isoquinolinol (3.6 g., 0.01 mole), benzyl bromide (1.71 g., 0.01 mole, 1.2 ml.) powdered anhydrous potassium carbonate (2.8 g., 0.02 mole) in ml. of acetone is refluxed for 72 hrs. and filtered. The filt-r'ate is concentrated under reduced pressure and the resulting residue stirred with petroleum ether (B.P. 30-60 C.) to provide a solid. Crystallization from a mixture of methanol-acetone-isopropanol (with decolorizing charcoal) aifords 3.2 g. of analytically pure 3 benzyloxy-6,7-dimethoxy-l-veratrylisoquinoline, M.P. 114.0-1 15.5 C. (corr.).

Analysis.Calcd. for C27H27NO5 (percent): C, 72.79; H, 6.11; N, 3.14. Found (percent): C, 72.72; H, 6.04; N, 3.14.

Ultraviolet: x (CHCl 348 (e, 5500); 244 (6, 60,600) millimicrons.

NMR: 6 (deuterochloroform, tetramethylsilane reference), 3.6-3.9 (4s, 12, OCH 4.4 (s, 2, CH 5.4 (s, 2, OCH 6.7-7.3 (11, ArH).

EXAMPLES 13-46 Additional exemplification of the compounds of the present invention are provided in the following Tables I and II. These compounds are obtained according to the procedures hereinabove described in Examples 1-10 from the indicated reactants.

TABLE 1.ADDIIIONAL ISOQUINOLINES Ex. No. R

(CH3) 2 CH- Reactants 15...- CH: (CHa)aC 16 C2Hr CH:-

17. (CH2)2CH CH:

18 n-CrHa CH:

19---- CH: CH1=CHCH2- 1 3 TABLE II-Cntlnued 1 4 iii R R Reactants 41 CH: CHaNH- 1-@A-dimethoxybenzylidene) 6,7-dimethoxy-3-isochromanone and N -methylhydra- 42.... CH; (CH3)zCHNH- 1-igidilfiethoxybenzylidene)-6,7-dimethoxy-3-isochromanone and N-isopropylhy- 43..- CH: (CHa)zN- 1-gglddlfigihoxybenzylidene)-6,7-dimethoxy-3-isochromanone and N,N-dimethyl- 44 CH3 (n-C4H9)2N 1-(3,4-dimethoxybenzylidene)-6,7-dimethoxy-3-isochromanone and N,N-di-n-butyl- It will be appreciated by those skilled in the art that specific embodiments disclosed in the foregoing specification are exemplary of other modifications which can be made without departing from the spirit and scope of the appended claims.

What is claimed is:

1. A compound selected from the group consisting of those having the formula wherein R is lower alkyl having up to 4 carbon atoms;

R is selected from the group consisting of hydroxy, amino, lower alkylamino having up to 4 carbon atoms, lower dialkylamino having up to 4 carbon atoms, lower alkyl having up to 4 carbon atoms, alkenyl having from 3 to 6 carbon atoms, cycloalkyl having from 3 to carbon atoms, phenylalkyl having up to 10 carbon atoms, and substituted phenylalkyl having up to 10 carbon atoms apart from the substituent, said substituent being in the 2-, 3-, 4-, 5-, or 6-'ring positions and being selected from the group consisting of halogen, lower alkyl having up to 4 carbon atoms, and methylenedioxy, or from 1 to 3 lower alkoxy groups having up to 4 carbon atoms each;

and pharmaceutically acceptable acid addition salts thereof.

2. The compound of the group defined in claim 1 which is 6,7-dimethoxy-2-methyl-l-veratryl 3(2H) isoquinolone.

3. The compound of the group defined in claim 1 which is 6,7-dimethoXy-2-methy1-l-veratryl 3(2H) isoquinolone hydrochloride.

4. The compound of the group defined in claim 1 which is 6,7-diethoxy 2 methyl-1,-(3,4-diethoxy)benzyl- 3 (2H) -isoquinolone.

5. The compound of the group defined in claim 1 which is 6,7'diethoxy 2 methyl-1-(3,4-diethoxy)benzyl- 3 (2H)-isoquinolone hydrochloride.

6. The compound of the group defined in claim 1 which is 2-allyl-6,7-dimethoxy-1-veratryl-3(2H) -isoquinolone.

'I. The compound of the group defined in claim 1 which is a 2-allyl-6,7-dimethoxy-l-veratryl 3(2H) isoquinolone hydrochloride.

8. The compound of the group defined in claim 1 which is 2-ethyl-6,7-dimethoxy-1-veratry1-3 (2H)-isoquinolone.

9. The compound of the group defined in claim 1 which is 2-ethyl-6,7-dimethoxy-1-veratryl-3 (2H)-isoquinolone hydrochloride.

10. The compound of the group defined in claim 1 which is 2cyclopropyl-6,7-dimethoxy-l-veratryl-3(2H)- isoquinolone.

11. The compound of the group defined in claim 1 which is 2-cyclopropyl-6,7-dimethoxy-1-veratryl-3 (2H)- isoquinolone hydrochloride.

12. The compound of the group defined in claim 1 which is 2-benzyl 6,7 dimethoxy-1-veratryl-3(2H) -isoquinolone.

13. The compound of the group defined in claim 1 which is 2-benzyl 6,7 dimethoxy-1-veratryl-3(2H)-isoquinolone hydrochloride.

14. The compound of the group defined in claim 1 which is 6,7-dimethoxy-2-(3,4 dimethoxyphenethyD-lveratryl-3 (2H) -isoquinolone.

15. The compound of the group defined in claim 1 which is 6,7-dimethoxy-2-(3,4-dimethoxyphenethyl) 1- veratryl-3 2H) -isoquinolone hydrochloride.

16. The compound of the gruop defined in claim 1 which is 2 amino-6,7-dimethoxy-l-veratryl-B (2H) isoquinolone.

17. The compound of the group defined in claim 1 which is 2-amino-6,7-dimethoxy 1 veratryl 3(2H)-isoquinolone hydrochloride.

18. The compound of the group defined in claim 1 which is 2-hydroxy-6,7-dimethoxy-l-veratryl 3 (2H) isoquinolone.

19. The compound of the group defined in claim 1 which is 2-hydroxy-6,7-dimethoxy 1 veratryl-3(2H)-isoquinolone hydrochloride.

References Cited UNITED STATES PATENTS 2,809,969 10/ 1957 Specter 260-289 R 3,301,857 1/1967 Berger 260289 R 3,480,634 11/1967 Finkelstein 260-288 R FOREIGN PATENTS 286,496 2/ 1963 Switzerland 260289 R OTHER REFERENCES DONALD G. DAUS, Primary Examiner US. Cl. X.R.

260-270 D, 270 R, 283 SY, 288 R, 289 R, 345.2, 521 R; 424-258 

